Wheelchairs are mobility devices that facilitate engaging in ordinary activities for disabled persons. Wheelchairs enable the persons to engage in ordinary daily activities such as moving around a home, going shopping, traveling, and the like. Conventional wheelchairs comprise tube frame construction having a frame, drive wheels, front castors, and a seating system including seat and back. The seat and back include cushions for seating support and comfort. Lateral positioners and head supports also can attach to the seating system depending upon the particular physical requirements of the individual using the wheelchair.
There is an increased focus on facilitating wheelchair users in ordinary and routine daily activities. This includes, for example access to storage cabinets, tables, and the like, which requires reaching above and below conventional heights. Some wheelchair devices accommodate this by allowing the wheelchair to be set for different heights. The drawback is that changing the height that is set for the wheelchair is often not practical. Yet the conventional and ordinary activities of most persons involve interacting with furniture, cabinets, and articles at differing heights.
Wheelchair construction has previously provided mechanisms to allow changing the seat height of the wheelchair. Generally, these involve mechanisms that vertically displace the seat up or down. Power or hydraulic cylinders operate to move the seat vertically, but may be different to control the particular positioning of the change in height.
While vertically adjustable seat systems enable a wheelchair user to reposition the seating, there are drawbacks to its use. Merely moving the seat vertically upward causes a change in the center of gravity. The wheelchair then tends to be come more tippy. “Tippy” refers to the tendency of the wheelchair to tip rearwardly. It is important generally for independent pushers to configure the wheelchair to be tippy. In such configuration, a substantial majority of the weight carried by the wheelchair is on the rear wheels. This makes the front wheels easier to elevate, for example, for going over curbs, carpeting, grass, or other surfaces. Raising the center of gravity tends to make the wheelchair increasingly tippy.
Accordingly, there is a need in the art for a balanced user-activated stability-compensated height-adjusting seating system on a wheelchair. It is to such that the present invention is directed.